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Start your free trial###### Sean Lafferty

3,029 Points# This is impossible

Please help, I jsut cant grasp this stuff :(

```
let numbers = [2,8,1,16,4,3,9]
var sum = 0
var counter = 0
// Enter your code below
while counter < numbers.count {
counter += 1
newValue = numbers.count()
sum = newValue +=1
}
```

## 1 Answer

###### Jennifer Nordell

Treehouse TeacherHi there! I see that you've been trying so let's take a look at the solution step by step. It's not impossible!

```
let numbers = [2,8,1,16,4,3,9]
var sum = 0
var counter = 0
// Enter your code below
while counter < numbers.count {
sum += numbers[counter]
counter += 1
}
```

Ok so we set up our while loop, which you did correctly as it passed step 1. There must be some confusion about the next step. We have a `sum`

variable which is started at 0. This makes sense as we haven't yet added anything to it. What we're wanting to do is create a running total and keep track of it.

The `numbers[counter]`

will pull a value from that index of the `numbers`

array which is already set up for us. Because we start with the counter at 0, the very first iteration will pull the number at the 0 index of the numbers array (which is 2) and add it to our sum. This gives us a value of 2 for the sum. Then we increment the counter which puts it at 1.

The next iteration will pull a value from `numbers`

at the index of 1, because that is our current value of counter. The number at the index of 1 is 8. It is now added to sum, which gives it a value of 10. This process will repeat until we've gotten every number out of the array and added its value to sum resulting in the sum of all elements of the array.

Hope this clarifies things!

## Sean Lafferty

3,029 Points## Sean Lafferty

3,029 PointsHero! Thankyou very much!